1. Technical Field
The present disclosure relates to aircraft.
2. Description of Related Art
In modern warfare tactical aircraft are an indispensable asset to military commanders. However, tactical aircraft are limited by, for example, fuel capacity, weaponry capacity and configuration, and maintenance intervals. In-flight refueling can extend combat operations. However, aircraft must still return to a ground base to rearm and to have maintenance performed. Similarly aircraft used in civilian applications such as crop-dusting, aerial police/traffic surveillance, and countering man-portable air-defense systems are also limited by their need to return to ground for maintenance, reconfiguration, etc.
These limitations are exacerbated in unmanned air vehicles (UAVs) and unmanned combat air vehicles (UCAVs). For simplicity, the abbreviation UAV will be used herein to refer to both unmanned air vehicles and unmanned combat air vehicles. With the advent of unmanned tactical aircraft, mission endurances have increased steeply due to the elimination of pilot fatigue as a limiting factor. This steep increase in endurance is particularly acute for intelligence, surveillance, and reconnaissance (ISR) missions and hunter-killer missions. But tactical UAVs configured for high endurance typically achieve endurance at the expense of speed and range, thus limiting the spectrum of situations in which they can be deployed. The limited range of some UAVs can be overcome by launching them from airborne transport vehicles.
The ability to recover and re-launch aircraft using an airborne mother ship would enable the aircraft to operate virtually indefinitely. Upon recovery, the aircraft could be refueled, rearmed and serviced aboard the mother ship, after which it could be re-launched to return to the battle theatre. In the case of manned aircraft, pilot changes could also be performed while the aircraft is docked with the mother ship. Historically, however, attempts at airborne recovery of aircraft have met with little, if any, success.
Attempts at airborne recovery include the FICON (Fighter Conveyor) experiments, in which the daughter aircraft had a hook on its upper surface that caught a trapeze hanging from the mother ship, the Akron and Macon (U.S. airships that carried fighters and captured them with a trapeze system), the Tom-Tom experiments, the Tupolev Zveno and the Firebee II drone, which deployed a parachute that could be snagged by a trapeze device hanging from a passing helicopter. Thus far, trapeze-based solutions are the only ones that have worked to bring the aircraft inside the mother ship. However, even these moderate successes failed to solve the major problems associated with traditional trapeze- or arm-based airborne recovery, in which the recovered aircraft's weight must be transitioned from its own lift to the mother ship. The transition typically happens close to the mother ship, due to the length of the recovery device, requiring the difficult connection to be made as the deployed aircraft transitions from “clean” air, to a turbulent wake and boundary layer surrounding the mother ship and finally to dead air where it cannot create sufficient lift for flight. These transitions through different types of air make it very difficult to control the aircraft being recovered.